T-4 Free Energy Flashcards
Define Gibb’s Free Energy
Amount of work a spontaneous process can do on its surroundings or the amount of work the surrounds must do to drive a nonspontaneous process
How is free energy related to enthalpy and entropy (equation)?
delta G = delta H - T•delta S
How is delta Gº related to delta G (equation)?
delta G = delta Gº + RT ln(Q)
How is delta Gº related to K (equation)?
delta Gº = -RT ln(K)
What is the sign of delta G when a process is spontaneous?
negative
At what temperature is a process spontaneous when…
delta H is positive
delta S is positive
At high temperatures -T delta S is larger than delta H
(T= delta H / delta S)
At what temperature is a process spontaneous when…
delta H is positive
delta S is negative
never spontaneous
At what temperature is a process spontaneous when…
delta H is negative
delta S is negative
Low temperature so that - delta H is greater than + (- of -) T delta S
(T= delta H / delta S is negative)
At what temperature is a process spontaneous when…
delta H is negative
delta S is positive
At all temperatures
What is the value for delta G when a system is at equilibrium?
delta G = 0
Is the following system shifting to the right, shifting to the left, or at equilibrium?
delta G is negative
Shift right
Is the following system shifting to the right, shifting to the left, or at equilibrium?
delta G is zero
at equilibrium
Is the following system shifting to the right, shifting to the left, or at equilibrium?
delta G is positive
shifting to the left
What is happening to the value of delta G as a reaction shifts to the left
The positive delta G is getting smaller as it heads towards delta G = 0
What is happening to the value of delta G as a reaction shifts to the right?
The magnitide of the negative delta G is getting smaller as it heads towards delta G = 0
What can you tell me about the value of K for a reaction with a negative delta Gº?
K > 1
delta Gº = -RT ln(K)
What can you tell me about the value of K for a reaction with a positive delta Gº?
K < 1
delta Gº = -RT ln(K)
What can you tell me about the value of K for a reaction with a delta Gº = 0?
K = 1
delta Gº = -RT ln(K)
Delta G for a process at low temperatures is negative. No product is observed to be forming. Commnet on the thermodynamic and kinetic favorability of the reaction.
The reaction is thermodynamically favorable (delta G is negative). Since is does not appear to proceed then it must by kinetically unfavorable (it is very slow).
